util/repair: add _notmuch_repair_crypto_payload_skip_legacy_display

[notmuch] / util / repair.c

diff --git a/util/repair.c b/util/repair.c
index f91c124415516139585b2b48ea00abe5875b7783..629e6f232e090371595e3924464e38d75df7fe61 100644 (file)
--- a/util/repair.c
+++ b/util/repair.c
@@ -18,4 +18,105 @@
  * Authors: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
  */
 
+#include <stdbool.h>
 #include "repair.h"
+
+
+static bool
+_notmuch_crypto_payload_has_legacy_display (GMimeObject *payload)
+{
+    GMimeMultipart *mpayload;
+    const char *protected_header_parameter;
+    GMimeTextPart *legacy_display;
+    char *legacy_display_header_text = NULL;
+    GMimeStream *stream = NULL;
+    GMimeParser *parser = NULL;
+    GMimeObject *legacy_header_object = NULL, *first;
+    GMimeHeaderList *legacy_display_headers = NULL, *protected_headers = NULL;
+    bool ret = false;
+
+    if (! g_mime_content_type_is_type (g_mime_object_get_content_type (payload),
+                                      "multipart", "mixed"))
+       return false;
+    protected_header_parameter = g_mime_object_get_content_type_parameter (payload, "protected-headers");
+    if ((! protected_header_parameter) || strcmp (protected_header_parameter, "v1"))
+       return false;
+    if (! GMIME_IS_MULTIPART (payload))
+       return false;
+    mpayload = GMIME_MULTIPART (payload);
+    if (mpayload == NULL)
+       return false;
+    if (g_mime_multipart_get_count (mpayload) != 2)
+       return false;
+    first = g_mime_multipart_get_part (mpayload, 0);
+    if (! g_mime_content_type_is_type (g_mime_object_get_content_type (first),
+                                      "text", "rfc822-headers"))
+       return false;
+    protected_header_parameter = g_mime_object_get_content_type_parameter (first, "protected-headers");
+    if ((! protected_header_parameter) || strcmp (protected_header_parameter, "v1"))
+       return false;
+    if (! GMIME_IS_TEXT_PART (first))
+       return false;
+
+    /* ensure that the headers in the first part all match the values
+     * found in the payload's own protected headers!  if they don't,
+     * we should not treat this as a valid "legacy-display" part.
+     *
+     * Crafting a GMimeHeaderList object from the content of the
+     * text/rfc822-headers part is pretty clumsy; we should probably
+     * push something into GMime that makes this a one-shot
+     * operation. */
+    if ((protected_headers = g_mime_object_get_header_list (payload), protected_headers) &&
+       (legacy_display = GMIME_TEXT_PART (first), legacy_display) &&
+       (legacy_display_header_text = g_mime_text_part_get_text (legacy_display), legacy_display_header_text) &&
+       (stream = g_mime_stream_mem_new_with_buffer (legacy_display_header_text, strlen (legacy_display_header_text)), stream) &&
+       (g_mime_stream_write (stream, "\r\n\r\n", 4) == 4) &&
+       (g_mime_stream_seek (stream, 0, GMIME_STREAM_SEEK_SET) == 0) &&
+       (parser = g_mime_parser_new_with_stream (stream), parser) &&
+       (legacy_header_object = g_mime_parser_construct_part (parser, NULL), legacy_header_object) &&
+       (legacy_display_headers = g_mime_object_get_header_list (legacy_header_object), legacy_display_headers)) {
+       /* walk through legacy_display_headers, comparing them against
+        * their values in the protected_headers: */
+       ret = true;
+       for (int i = 0; i < g_mime_header_list_get_count (legacy_display_headers); i++) {
+           GMimeHeader *dh = g_mime_header_list_get_header_at (legacy_display_headers, i);
+           if (dh == NULL) {
+               ret = false;
+               goto DONE;
+           }
+           GMimeHeader *ph = g_mime_header_list_get_header (protected_headers, g_mime_header_get_name (dh));
+           if (ph == NULL) {
+               ret = false;
+               goto DONE;
+           }
+           const char *dhv = g_mime_header_get_value (dh);
+           const char *phv = g_mime_header_get_value (ph);
+           if (dhv == NULL || phv == NULL || strcmp (dhv, phv)) {
+               ret = false;
+               goto DONE;
+           }
+       }
+    }
+
+ DONE:
+    if (legacy_display_header_text)
+       g_free (legacy_display_header_text);
+    if (stream)
+       g_object_unref (stream);
+    if (parser)
+       g_object_unref (parser);
+    if (legacy_header_object)
+       g_object_unref (legacy_header_object);
+
+    return ret;
+}
+
+GMimeObject *
+_notmuch_repair_crypto_payload_skip_legacy_display (GMimeObject *payload)
+{
+    if (_notmuch_crypto_payload_has_legacy_display (payload)) {
+       return g_mime_multipart_get_part (GMIME_MULTIPART (payload), 1);
+    } else {
+       return payload;
+    }
+}